Watershed impacts irrigation

By Merry Thomas, Fallon Star Press, via RGJ.com
October 3, 2008

If the dry weather conditions continue into fall and early winter, the region could face a slower water release than usual and create the possibility of diverting water from the Truckee River in December, according to TCID Project Manager Dave Overvold.

Releases from Lahontan Dam resumed Wednesday after having been curtailed for nearly two weeks. As of Friday, Sept. 19, which is the latest numbers available, storage was 28,361 acre-feet. The amount of water and rate at which it is released from Lahontan depends on inflow from the Carson River, Overvold said.

The Lahontan Dam is down this season by about two-thirds the average, historically. This means it's likely area farmers will receive deliveries short by about 2,000 acre-feet this season. The maximum Truckee Canal diversion allowed by the U.S. Bureau of Reclamation is 350 cubic feet per second, which is more than will be available by the time the flow reaches the Derby Dam, the TCID Web site stated.

"We want to keep water diverted from the Truckee River at a minimum," Overvold said.

Water gets diverted from Lake Tahoe or from Prosser or Boca reservoirs to make up the difference when there isn't enough naturally occurring water, such as rain. Tuesday, for instance, the water arriving at Derby Dam was released at 133 cfs below the dam. The rate of release from Tahoe is about 189 cfs, and the rate of flow below Derby is expected to drop this month to 113 cfs.